First mistake I made in my new pantry: believed the 12-inch rule. Every blog said 12 inches between shelves is standard. I didn't measure a single can. Now I've got a shelf with 6 inches of air above the tomato paste and no room for the cereal boxes.
Next time, I'm measuring what I actually store. Grab a tape measure and a few items: canned goods, cereal boxes, maybe a blender. Put them on a table and stack them like you would on a shelf. Don't guess. I did this in my garage last week and found my tallest regular item is a 10-inch cereal box. But I also have a 13-inch jug of olive oil and a 15-inch box of pasta. So my spacing isn't uniform—I'm setting 13 inches for the tall stuff and 10 for the everyday.
And don't forget the shelf thickness. I didn't account for the 1-inch board, so my 12-inch spacing actually gave me 11 inches of clearance. That cereal box scraped the bottom of the shelf above. So measure the actual gap from the top of one shelf to the bottom of the next—not the distance between the boards' tops.
Another thing: I left a 3-inch gap above the cereal box because I measured the box, not the shelf above it. That's wasted vertical space. I use every inch now, and I still have room to add another shelf. My pantry is 84 inches tall; I fit 5 shelves with 12 inches of spacing, but if I had measured, I could've fit 6 by adjusting for my actual stack.
Also, think about what sits on the shelf under the next one. Your pasta jars might be 8 inches, but the shelf above is at 12—so you get 4 inches wasted. I fixed it by grouping items by height and spacing accordingly. Cheap wire shelves are adjustable, so use that.
Here's the thing: there's no universal number. My pantry now has shelves at 10, 13, and 16 inches apart. Does it look as neat as the magazines? No. Does it hold twice as much? Yes.
Don't trust the rule. Measure your cans. And if you're still planning a pantry, check how I almost lost the whole wall with my metal bathroom shelf spacing mistake. For a more complete approach, see Custom Pantry Shelving: Plan Depth, Spacing, and Load Before You Build.
One more thing: if you're using wire shelves, note the gaps. They let light through, but also dust. And they don't support small bottles as well—they tip. I switched to solid for most shelves.
So my advice? Measure twice, space once. And if you already messed up like me, just move the brackets. Is it a pain? Yeah. But it beats flipping cans every time you reach for a can of beans.